| Union Hill G-3-286732 | Geosouthern Operating II, LLC only | Giddings (Austin Chalk, Gas) | Washington | 1 | 380K | 5.62M | Feb 2019 – Aug 2026 |
| Brown-Donner Unit A-567 G-6-153267 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 370K | 2.15M | Dec 1994 – Aug 1998 |
| Arco Fee Unit A-121 G-6-151133 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Jasper | 1 | 254K | 2.6M | May 1994 – Mar 2000 |
| Mahlmann-Walther Unit G-3-141715 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 252K | 2.3M | by Jan 1993 – Aug 1999 |
| Pocahontas Unit G-3-161527 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 245K | 929K | Nov 1996 – Aug 1999 |
| Boeker-Union Hill AW-D G-3-294660 | Geosouthern Operating II, LLC only | Giddings (Austin Chalk, Gas) | Washington | 1 | 236K | 4.33M | Dec 2022 – Aug 2026 |
| Terry, H. L. Unit G-3-146621 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Brazos | 1 | 215K | 2.05M | Jul 1993 – Aug 1999 |
| Arco Fee G-3-148623 | Union Oil Company of California only | Felicia Creek (y-4 Sand) | Liberty | 1 | 213K | 3.49M | Nov 1993 – Jul 1995 |
| Allen G-3-145818 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Brazos | 1 | 188K | 1.3M | May 1993 – Aug 1999 |
| Franus Unit G-3-156437 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Grimes | 1 | 187K | 2.41M | Sep 1995 – Feb 2000 |
| McCullough-McCullough 'A' G-3-145083 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Brazos | 1 | 187K | 1.49M | by Jan 1993 – Feb 2000 |
| Boeker-Union Hill AW-A G-3-294644 | Geosouthern Operating II, LLC only | Giddings (Austin Chalk, Gas) | Washington | 1 | 187K | 2.49M | Dec 2022 – Aug 2026 |
| Boeker-Union Hill AW-C G-3-294773 | Geosouthern Operating II, LLC only | Giddings (Austin Chalk, Gas) | Washington | 1 | 184K | 3.16M | Dec 2022 – Aug 2026 |
| Cannon Unit G-3-155696 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Grimes | 1 | 179K | 1.28M | Jun 1995 – Aug 1999 |
| Jawbreaker Unit G-3-151736 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 174K | 1.3M | Sep 1994 – Aug 1999 |
| Champion Int'l Unit A-1175 G-6-155820 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 159K | 833K | Jul 1995 – Jan 1999 |
| Mueller-Korth Unit G-3-148108 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Lee | 1 | 155K | 751K | Jan 1994 – Aug 1999 |
| Champion a-334 Unit G-6-152455 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 143K | 1.21M | Jul 1994 – Dec 1998 |
| Brazos Coal Ltd.-Terry "B" Unit G-3-146180 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Brazos | 1 | 134K | 915K | Jun 1993 – Aug 1999 |
| Boeker-Union Hill AW-B G-3-294645 | Geosouthern Operating II, LLC only | Giddings (Austin Chalk, Gas) | Washington | 1 | 128K | 2.28M | Dec 2022 – Aug 2026 |
| Wagnon Unit G-3-153709 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Grimes | 1 | 127K | 966K | Feb 1995 – Aug 1999 |
| Texas A&m University G-3-248058 | Union Gas Operating Company only | Bleakwood, South (Middle Wilcox) | Newton | 1 | 127K | 3.13M | Dec 2008 – Jun 2023 |
| Force, E. J. Unit G-3-118949 | Tri-Union Development Corp. only | Alvin, North (8550) | Brazoria | 1 | 109K | 261K | by Jan 1993 – Nov 1998 |
| Gibbs Bros. Unit G-6-149857 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Newton | 1 | 88.2K | 472K | May 1994 – Jan 1999 |
| Arco-Fee a-990 Unit G-6-153675 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Jasper | 1 | 77.7K | 1.04M | Dec 1994 – Aug 1998 |
| Union Ranch G-4-251688 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 75K | 5.61M | Mar 2009 – Aug 2026 |
| Hoelscher, Alice B. G-3-143662 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Burleson | 1 | 67.3K | 723K | by Jan 1993 – May 1996 |
| Bscu USA 27316 G-6-156998 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Sabine | 1 | 65K | 709K | Mar 1995 – Dec 1998 |
| Roosevelt Unit G-3-151956 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 61.5K | 671K | May 1994 – Sep 1999 |
| Embesi Unit G-3-174197 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 59.9K | 502K | Jun 1999 – Oct 1999 |
| Union Ranch-Lopez G-4-226329 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 52.4K | 3.21M | Feb 2007 – Aug 2026 |
| State Tract 563-L G-2-114520 | Reunion Energy Company only | Matagorda Block 563-L (6517) | Matgrda IS-LB | 1 | 52.3K | 127K | by Jan 1993 – Apr 1994 |
| McCrary Unit G-3-156476 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Grimes | 1 | 39.1K | 356K | Oct 1995 – Aug 1999 |
| Svruc Unit G-5-218074 | Union Oil Company of California only | Van (Rodessa) | Van Zandt | 1 | 37.7K | 372K | Apr 2006 – Jan 2020 |
| Yelderman-Bredthauer Unit G-3-142127 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Washington | 1 | 36.7K | 707K | by Jan 1993 – Sep 2000 |
| Warrenton Amarado Unit G-3-147182 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Fayette | 1 | 36.2K | 1.04M | Oct 1993 – Oct 1996 |
| Heath G-5-139694 | Old Union Operating Company only | Winkler, S.(cotton Valley Lime) | Freestone | 1 | 34K | 4.51M | by Jan 1993 – Aug 2026 |
| Union Ranch G-4-186078 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 33.4K | 5.2M | Nov 2001 – Aug 2026 |
| Arco Fee Unit A-15 G-6-163658 | Union Pacific Resources Company only | Brookeland (Austin Chalk, 8800) | Jasper | 1 | 31.5K | 1.34M | Mar 1997 – Jul 1999 |
| BP Fee A-6 G-3-212203 | Union Gas Operating Company only | Buna, West (Wilcox) | Jasper | 1 | 31K | 405K | Jun 2005 – Nov 2009 |
| Williams, Henry Gas Unit G-5-141886 | Old Union Operating Company only | Teas (Cotton Valley) | Freestone | 1 | 28.6K | 1.3M | by Jan 1993 – Aug 2026 |
| Howell-Anderson G-5-141212 | Old Union Operating Company only | Winkler, S.(cotton Valley Lime) | Freestone | 1 | 24.9K | 2.21M | by Jan 1993 – Jun 2026 |
| Anderson Gas Unit G-5-46571 | Old Union Operating Company only | Reka (Cotton Valley Lime) | Navarro | 1 | 24.8K | 805K | by Jan 1993 – Jun 2026 |
| Union Ranch-Moreno GU G-4-192640 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 23.9K | 4.03M | Dec 2002 – Aug 2026 |
| Arco Fee G-3-143979 | Union Oil Company of California only | Felicia Creek (y-6 Sand) | Liberty | 1 | 21.2K | 702K | by Jan 1993 – Aug 1995 |
| Union Ranch State GU G-4-190647 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 20.1K | 3.51M | Aug 2002 – Aug 2026 |
| BP Stark A-370 G-3-245856 | Union Gas Operating Company only | Dempsey Creek (Wilcox) | Newton | 1 | 18.5K | 930K | Oct 2008 – Jan 2021 |
| Union Ranch G-4-188672 | Mountain V Texas, LLC only | Tiffany (Wilcox Carrizo) | Webb | 1 | 18.2K | 3.27M | Apr 2002 – Aug 2026 |
| Waltman-Chance Farms Unit G-3-144378 | Union Pacific Resources Company only | Giddings (Austin Chalk, Gas) | Brazos | 1 | 17.3K | 89K | by Jan 1993 – Feb 1997 |
| Davis Heirs G-5-119014 | Old Union Operating Company only | Rischers Store (Davis Sand) | Freestone | 1 | 16.9K | 635K | by Jan 1993 – Aug 2026 |